Move rigid body gear using particles
I was just looking into this over the weekend. I believe a recent tutorial on Vit Prochazka's youtube channel has the answer you seek. I'd love to try and explain it here, bit it is quite convoluted and it requires the Animation Nodes add-on.

Seems an elegant solution though, I hope it helps:

https://www.youtube.com/watch?v=G1ysjPeLKSQ&amp;t